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Biomedical subjects

G Watt

Publications and source records attributed to G Watt.

At least 109 records · Page 6Linked to original sources

Amodiaquine less effective than chloroquine in the treatment of falciparum malaria in the Philippines.

Amodiaquine was compared to chloroquine in two groups of Filipino patients with uncomplicated falciparum malaria. Every patient received 25 mg/kg of base orally given over three days. In a hospital study, all eight patients receiving chloroquine cleared their parasitemia by day 6, but six of eight patients receiving amodiaquine failed to clear parasitemia and in four patients there was no response at all (RIII resistance); this difference was significant (P less than 0.01). In a village based study, there was initial clearing of parasitemia in each patient. However, recrudescent infection occurred in all five patients receiving amodiaquine (RI resistance). Five of six falciparum infections were sensitive to chloroquine, while parasitemia reappeared in one patient. In this village, resistance to amodiaquine was significantly more common than resistance to chloroquine (P less than 0.05). To our knowledge, this is the first report of amodiaquine being substantially worse than chloroquine in the treatment of Plasmodium falciparum infection.

Adolescent↗

Bites by the Philippine cobra (Naja naja philippinensis): an important cause of death among rice farmers.

We investigated mortality from cobra (Naja naja philippinensis) bite among Filipino rice farmers. Village records in one area were examined and we conducted a careful survey in this and two additional areas among inhabitants at varying risk for snakebite. The death rate from cobra bite was estimated to be as high as 107.1 deaths per 100,000 population per year at one site. Most victims were young (median age 17) and 98% were males. Only 8% of the victims studied reached a hospital. The confirmed death rate averaged 53.8/100,000 for the three populations.

Adolescent↗

In vitro drug response of Plasmodium falciparum in the Philippines: increased resistance to amodiaquine.

A long term study was carried out at San Lazaro Hospital, Manila, Philippines, monitoring the in vitro response of Plasmodium falciparum to chloroquine, amodiaquine, mefloquine, and quinine. The in vitro effective dose giving 50% inhibition of schizogony was: 0.68 X 10(-6) M/liter blood for chloroquine; 0.18 X 10(-6) for amodiaquine; 0.2 X 10(-6) for mefloquine; and 1.12 X 10(-6) for quinine. The percent of isolates determined to be resistant in vitro was 85.2% for chloroquine, and 1.2% for both mefloquine and quinine. These figures were relatively unchanged over the course of 3 years studied. The in vitro resistance rate to amodiaquine increased from 5.1% in 1982 to 22.2% in 1984.

Amodiaquine↗

Positive response to edrophonium in patients with neurotoxic envenoming by cobras (Naja naja philippinensis). A placebo-controlled study.

To study the ability of anticholinesterase drugs to reverse the potentially fatal paralytic effects of cobra venom, we conducted a placebo-controlled, double-blind crossover trial of intravenous edrophonium (Tensilon) in 10 adults with neurotoxic envenoming caused by bites of the Philippine cobra (Naja naja philippinensis). There was significantly more improvement in ptosis and endurance of upward gaze after edrophonium than after placebo. Five minutes after injection, the mean difference (+/- SD) in the percentage of the iris that was uncovered was 39 +/- 5.47 (70 vs. 31 percent; P less than 0.01), and the mean difference in the number of seconds of upward gaze was 33.1 +/- 9.29 (39.7 vs. 6.6 seconds; P less than 0.01). The expiratory and inspiratory pressures, forced vital capacity, and ability to cough, speak, and swallow also improved after edrophonium. In both the patients who were studied electromyographically, pretreatment and postplacebo responses were typical of myasthenia gravis and became normal after edrophonium. We conclude that anticholinesterases are beneficial in the management of neurotoxic envenoming by Asian cobras (Naja naja), and we recommended a test of edrophonium in any patient with signs of neurotoxic envenoming after snakebite.

Adolescent↗

Praziquantel in treatment of cerebral schistosomiasis.

The effectiveness of standard single-day praziquantel treatment (60 mg/kg) was prospectively evaluated in nine patients with seizures caused by cerebral Schistosoma japonicum infection. Eight patients were cured when discharged from the study, an average of 6 months after receiving praziquantel. They were seizure-free in the absence of anticonvulsants, their electroencephalograms were normal, and no major abnormalities could be detected on neurological examination. Serial computed tomography scanning revealed rapid dissipation of cerebral oedema and complete or near-complete resolution of mass lesions. No serious adverse effects of praziquantel were encountered. The ninth patient was not cured but improved greatly in the months after treatment. Thus, single-day treatment with praziquantel is safe and effective in cerebral schistosomiasis.

Adult↗

Nonresolution of an amebic liver abscess after parasitologic cure.

A 43-year-old Filipino male was admitted to a Manila hospital with a 1 month history of epigastric pain and fever, and was found to have a palpable epigastric mass. Computerized tomography revealed a large hepatic abscess which serologically was shown to be amebic. Chemotherapy resulted in clinical cure and an initial reduction in size of the liver abscess. However, resolution of the abscess cavity did not occur, and on closed needle aspiration, 80 cc of characteristic amebic pus was recovered. Parasitological cure without complete repair of the abscess cavity itself raises questions concerning the potential danger of clinically silent residua and the role of therapeutic aspiration in the management of amebic liver abscesses.

Adult↗

Evaluation of a synthetic oligonucleotide probe for diagnosis of Plasmodium falciparum infections.

A radiolabeled synthetic oligonucleotide was evaluated as a diagnostic probe specific for Plasmodium falciparum using blood samples lysed directly on nitrocellulose filters. The probe technique successfully diagnosed malaria in experimentally infected chimpanzees that had 0.001% parasitemias (50 parasites/microliter) as determined by blood smears, and in 1 chimpanzee whose blood smear was negative, but whose blood was culture-positive for P. falciparum. In a double blind study of 50 patient samples from the Philippines, the probe results correlated well with blood smear results when the autoradiographs were read after 4-8 hr exposure. The results indicate that the oligonucleotide probe may be useful in the rapid and specific diagnosis of P. falciparum infection.

Animals↗

Cardiopulmonary involvement rare in severe Schistosoma japonicum infection.

In a prospective study, 65 consecutive patients hospitalized with Schistosoma japonicum infection were evaluated for evidence of cardiopulmonary involvement. Thirty-two patients had evidence of severe liver dysfunction while 11 patients had portal hypertension only. Of these 43 patients with hepatosplenic disease, only one patient had pulmonary hypertension. Cardiopulmonary involvement is relatively uncommon in severe S. japonicum infections.

Adolescent↗

Delayed type hypersensitivity (DTH) to type II collagen (CII) in DBA-1 mice.

Sensitization of DBA-1 mice with Type II collagen (CII) in complete Freund's adjuvant can cause polyarthritis. A possible link between CII-induced arthritis and delayed type hypersensitivity (DTH) has been suggested, so we decided to investigate the susceptibility of DBA-1 mice to CII induced DTH reactions. The mice were primed with a dose of 10 micrograms CII i.p. 4 days before challenging with 40 micrograms CII in the ear. Swelling was measured 48 h later and was found to be reproducible. Responsiveness to CII could be transferred with whole spleen cell populations from primed animals or with enriched spleen T cells, thus confirming the cellular nature of the reaction. Lymph node cells from CII/CFA footpad immunized animals were restimulated with CII in vitro. These cells were able to passively transfer DTH sensitivity in vivo and exhibited specificity for this antigen in vitro in proliferation assays.

Animals↗

Seasnake bites in a freshwater lake.

One species of venomous seasnake, Hydrophis semperi, is found in Lake Taal, a large freshwater lake in the Philippines. The first series of seasnake bites occurring in freshwater is described. In one small fishing village, there were eight definite bites and one probably attributable death. In three of the eight patients, specific antibodies to Hydrophis venom were demonstrated. In contrast to previous seasnake studies, there was an absence of asymptomatic cases. The possible public health importance of freshwater seasnake bites in the Philippines needs further investigation.

Adolescent↗

Protection by ipratropium bromide and metaproterenol against methacholine and histamine bronchoconstriction.

To establish relative protection against methacholine and histamine, 40 micrograms of ipratropium bromide, an anticholinergic compound, 1.3 mg of metaproterenol or placebo aerosols were administered by metered-dose inhaler prior to inhalation challenge with methacholine or histamine in nine asthmatic subjects. Double-blind, randomized challenges were performed. Subjects required a mean methacholine dose of 1.72 +/- 0.73 and 2.46 +/- 0.72 (Ln inhalation units), and mean histamine dose of 2.16 +/- 0.65 and 2.68 +/- 0.49, to cause a drop of 20% and 35% respectively in the FEV1 following the placebo. In the methacholine challenges, both ipratropium bromide and metaproterenol had significant protection as compared to placebo (P less than 0.001). There was no statistical difference in the degree of protection against methacholine between ipratropium bromide and metaproterenol. In histamine challenges, metaproterenol had significant protection as compared to the placebo, while ipratropium bromide did not protect against histamine.

Adolescent↗